Plusnet Hub Two randomly drops ethernet port then reconnects it

[#1]

I recently got a replacement Hub Two for Full Fibre, and I've noticed that whichever ethernet port I'm connected to drops out and then reconnects seemingly at random. Here's a relevant part of the hub's event log:

10:31:04, 26 Sep.

A device connected to Ethernet port 3

10:31:04, 26 Sep.

Wire Lan Port 3 up, Speed 100 Mbps

10:31:03, 26 Sep.

DHCP device Connected: 192.168.1.209, 3c:f8:62:e7:b9:40, DAVID-DELL2017

10:31:03, 26 Sep.

DHCP device Connected: 192.168.1.177, 48:4d:7e:cb:f7:50, DAVID-DELL2017

10:31:02, 26 Sep.

LAN [ADD] ARP 192.168.1.209 with 3c:f8:62:e7:b9:40 from br0(eth1)

10:31:02, 26 Sep.

Lan IPv6 Neighbour Discovery events: NEIGHBOR_SOLICIT

10:31:02, 26 Sep.

LAN [ADD] ARP 192.168.1.177 with 48:4d:7e:cb:f7:50 from br0(eth2)

10:31:02, 26 Sep.

ARP [add] br0(eth1) 192.168.1.209 3c:f8:62:e7:b9:40

10:31:02, 26 Sep.

DHCP device Disconnected: 192.168.1.177, 48:4d:7e:cb:f7:50, <my pc name here>

10:31:02, 26 Sep.

Receive a DHCP request

10:31:01, 26 Sep.

A device disconnected from Ethernet port 3

10:31:01, 26 Sep.

Wire Lan Port 3 down, Speed 10 Mbps

Plusnet support say it could be my cable, but it's a quality product that's been fine for at least 2 years. Any thoughts anyone?

TIA

[#2]

I can't say too much on what could be causing this, hopefully someone else might, but a couple of comments.

I notice that it's negotiating 100Mbps at one point and 10Mbps at another.  The other one is that I've had quality, branded cables and other products fail a lot sooner than 2 years before now.  It would definitely be worth trying another cable as it's a quick, easy and cheap item to rule out.

Something else that may be able to cause something like this is the network port on your PC.  From the name of the device is that a Dell from 2017?

[#3]

@Jimsy what's the device (PC) you're having problems with ? particularly what is the make & model of the network card ?

It seems to be having problems negotiating the correct speed 

10:31:04, 26 Sep.

A device connected to Ethernet port 3

10:31:04, 26 Sep.

Wire Lan Port 3 up, Speed 100 Mbps

A device disconnected from Ethernet port 3

10:31:01, 26 Sep.

Wire Lan Port 3 down, Speed 10 Mbps

edit: looks like @pjmarsh types faster than me but is on the same track

and whatever the PC is , it seems to have two nics ( or at least two MACs )

from the MAC's , one is definitely Dell ( on-board nic ? ) , the other is Intel

[#4]

Hi pjmarsh - many thanks for the speedy response. Couldn't reply earlier.

Bit more background: This is the second Hub Two since June, when fibre was installed. Before that, I never had a LAN issue with my old Netgear hub, or with the first Hub Two supplied in June, but that developed a different issue where it would stop serving internet via Wi-Fi, although ethernet was working just fine. The PC is a Dell Inspiron from 2017, with onboard ethernet and Wi-Fi - not ideal, as I can't exactly swap out anything. It's one of those desktop machines that are effectively a laptop in a desktop case. No slots, period!

So, what happens is that ethernet drops out, and then Wi-Fi cuts in automatically, which probably explains the 2 MAC addresses. Then seconds later ethernet comes back.

I will try a different cable anyway, but unless the event log is misleading, it seemed that the port on the hub went down first, going by the timings?

[#5]

Hi MisterW:

Thanks for the reply - see my comments in reply to pjmarsh.

[#6 · Accepted solution]

@Jimsy does this help https://www.dell.com/community/en/conversations/inspiron/ethernet-wired-connection-keeps-disconnecti...

[#7]

Hi MisterW: I'll check this out. My onboard ethernet is definitely a Realtek PCIe FE Family Controller! But the curious thing is this only started with the replacement Hub Two.

Thanks!

PS: settings changed per article, and will monitor.

[#8]

I've been checking the hub's event log for nearly 30 mins after changing the adapter settings, and no disconnects! Just the usual DCHP requests. Will continue to monitor this, but thanks to both of you for pointing me in the right direction.